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HizookRobotics writes "Inflatable robots have the potential to be low-cost, lightweight, extremely powerful, and yet 'human safe' — in other words, perfect for many robotics applications. Here are two new examples: a 15-foot-long walking robot (a Pneubot named Ant-Roach) and a complete, inflatable robot arm (plus hand). Both of these robots were developed by Otherlab as part of their 'pneubotics' project (in collaboration with Meka Robotics and Manu Prakash at Stanford University), with some funding from DARPA's Maximum Mobility and Manipulation program. These robots use textile-based, inflatable actuators that contract upon inflation into specially-designed shapes to effect motion. Since these robots are built out of lightweight fabric-and-air structural members and powered via pneumatics or hydraulics, they exhibit large strength-to-weight ratios. For example, Ant-Roach is less than 70 lbs and can probably support up to 1000 lbs; the inflatable robot arm is less than 2 lbs and can lift a few hundred pounds at 50-60 psi."

So a few brief items (that are updated in the Hizook article [hizook.com]): The collaborator at Stanford is Manu Prakash; the inflatable actuators actually contract (not expand); they can be powered by either pneumatics or hydraulics; and Ant-Roach can probably support up to 1000 lbs (a bit more than just a few riders).

So, it looks like a giant blue monster out of the darker parts of Japanese adult animation, sounds like dance music played on cheap speakers, walks slowly, and, with that size:weight ratio, probably doesn't do well on windy days. Its "walk on water" demo was a little painful, too.

It's very cool, but I don't envy the guy who has to put together the sales pitch.

The technology could be used to liven up those big balloons they use in parades. Those things are tethered anyway, some hoses could be added to a few of the lines. It could also be used to making a silly version of a loch ness style critter that could be connected to a neutrally buoyant sled with compressed air tanks to power movement. Or you could make fun house critters that could grab people without hurting them.

Since they don't include the weight of the compressors that they're tethered to, and the power generation for them. So, cool toys, but they're not going to come stomping down Main Street any time soon, unless they're trailing a reeeeeally long extension cord.

Lightweight, dextrous, "safe" and strong... Granted, it's not got the full range of motion a human arm needs, yet, but this is interesting work. A small pneumatic compresser should be belt- or backpack-mountable, and then it would just need the control and processing electronics. Admittedly that's still kind of a big problem, but at a limb weight of 2lbs, this technology could be an interesting alternative to the "full-metal" approach of current limbs.

A difficulty with pneumatic actuators like this is that, even at the 50-60 psi they are using, they aren't terribly stiff (i.e., force vs displacement, like Hooke's Law) in the same way that motors and geartrains are in conventional prosthetics. A little compliance is good when we're talking about prosthetics, but I think users would find this unacceptably spongey. The problem is that you have a compressible fluid in a compliant envelope. They can provide force, certainly, but to hold position in the fac

The problem is that you have a compressible fluid in a compliant envelope.

One approach to this issue is to add lockable hard sliders. They act as idlers when unlocked but when engaged provide the required stiffness. For many applications they can be plastic and won't add huge amounts of weight, and the locking mechanism could itself be pneumatically controlled, so it's a relatively small number of additional valves.

You could probably measure the position of such a system with a tension strip. If you put a few of them around the arm you could determine the direction it's pointing at with fairly simple math. And it's a very cheap solution.

Where would one purchase the air valves to make one of these ? Are these low cost items or expensive specialist things.

Ordinary solenoid on/off air valves are widely used, easily available and cheap. Grainger stocks them, and they show up in surplus stores. Proportional air valves are somewhat exotic items. [proportionair.com]

From the video, it looks like the robot's legs are controlled through simple on-off valves (notice the clicks and the jerky leg motion) but the trunk has full proportional control and feedback.

Precision pneumatics is effective but not used all that much. Most pneumatic actuators are a simple solenoid valve controll